28 results on '"Robert J. Pabst"'
Search Results
2. Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA
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Thomas A. Spies, Eric White, Alan Ager, Jeffrey D. Kline, John P. Bolte, Emily K. Platt, Keith A. Olsen, Robert J. Pabst, Ana M.G. Barros, John D. Bailey, Susan Charnley, Jennifer Koch, Michelle M. Steen-Adams, Peter H. Singleton, James Sulzman, Cynthia Schwartz, and Blair Csuti
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adaptation ,ecosystem services ,landscape ,management ,wildfire ,Biology (General) ,QH301-705.5 ,Ecology ,QH540-549.5 - Abstract
Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landscape in the eastern Cascades of Oregon. Our model incorporated existing models of vegetation succession and fire spread and information from original empirical studies of landowner decision making. Our findings indicate that alternative management strategies can have variable effects on landscape outcomes over 50 years for fire, socioeconomic, and ecosystem services metrics. For example, scenarios with federal restoration treatments had slightly less high-severity fire than a scenario without treatment; exposure of homes in the wildland-urban interface to fire was also slightly less with restoration treatments compared to no management. Treatments appeared to be more effective at reducing high-severity fire in years with more fire than in years with less fire. Under the current management scenario, timber production could be maintained for at least 50 years on federal lands. Under an accelerated restoration scenario, timber production fell because of a shortage of areas meeting current stand structure treatment targets. Trade-offs between restoration outcomes (e.g., open forests with large fire-resistant trees) and habitat for species that require dense older forests were evident. For example, the proportional area of nesting habitat for northern spotted owl (Strix occidentalis) was somewhat less after 50 years under the restoration scenarios than under no management. However, the amount of resilient older forest structure and habitat for white-headed woodpecker (Leuconotopicus albolarvatus) was higher after 50 years under active management. More carbon was stored on this landscape without management than with management, despite the occurrence of high-severity wildfire. Our results and further applications of the model could be used in collaborative settings to facilitate discussion and development of policies and practices for fire-prone landscapes.
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- 2017
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3. Spatiotemporal dynamics of simulated wildfire, forest management, and forest succession in central Oregon, USA
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Ana M. G. Barros, Alan A. Ager, Michelle A. Day, Haiganoush K. Preisler, Thomas A. Spies, Eric White, Robert J. Pabst, Keith A. Olsen, Emily Platt, John D. Bailey, and John P. Bolte
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agent-based model ,Deschutes National Forest ,Flammap ,minimum travel time ,state-and-transition model ,Biology (General) ,QH301-705.5 ,Ecology ,QH540-549.5 - Abstract
We use the simulation model Envision to analyze long-term wildfire dynamics and the effects of different fuel management scenarios in central Oregon, USA. We simulated a 50-year future where fuel management activities were increased by doubling and tripling the current area treated while retaining existing treatment strategies in terms of spatial distribution and treatment type. We modeled forest succession using a state-and-transition approach and simulated wildfires based on the contemporary fire regime of the region. We tested for the presence of temporal trends and overall differences in burned area among four fuel management scenarios. Results showed that when the forest was managed to reduce fuels it burned less: over the course of 50 years there was up to a 40% reduction in area burned. However, simulation outputs did not reveal the expected temporal trend, i.e., area burned did not decrease progressively with time, nor did the absence of management lead to its increase. These results can be explained as the consequence of an existing wildfire deficit and vegetation succession paths that led to closed canopy, and heavy fuels forest types that are unlikely to burn under average fire weather. Fire (and management) remained relatively rare disturbances and, given our assumptions, were unable to alter long-term vegetation patterns and consequently unable to alter long-term wildfire dynamics. Doubling and tripling current management targets were effective in the near term but not sustainable through time because of a scarcity of stands eligible to treat according to the modeled management constraints. These results provide new insights into the long-term dynamics between fuel management programs and wildfire and demonstrate that treatment prioritization strategies have limited effect on fire activity if they are too narrowly focused on particular forest conditions.
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- 2017
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4. Evaluating carbon storage, timber harvest, and habitat possibilities for a Western Cascades (USA) forest landscape
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Jeffrey D. Kline, Mark E. Harmon, Thomas A. Spies, Anita T. Morzillo, Robert J. Pabst, Brenda C. McComb, Frank Schnekenburger, Keith A. Olsen, Blair Csuti, and Jody C. Vogeler
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- 2016
- Full Text
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5. Tree species diversity increases with conspecific negative density dependence across an elevation gradient
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Joseph A. LaManna, F. Andrew Jones, David M. Bell, Robert J. Pabst, and David C. Shaw
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Climate ,Biodiversity ,Forests ,Ecology, Evolution, Behavior and Systematics ,Ecosystem ,Trees - Abstract
Elevational and latitudinal gradients in species diversity may be mediated by biotic interactions that cause density-dependent effects of conspecifics on survival or growth to differ from effects of heterospecifics (i.e. conspecific density dependence), but limited evidence exists to support this. We tested the hypothesis that conspecific density dependence varies with elevation using over 40 years of data on tree survival and growth from 23 old-growth temperate forest stands across a 1,000-m elevation gradient. We found that conspecific-density-dependent effects on survival of small-to-intermediate-sized focal trees were negative in lower elevation, higher diversity forest stands typically characterised by warmer temperatures and greater relative humidity. Conspecific-density-dependent effects on survival were less negative in higher elevation stands and ridges than in lower elevation stands and valley bottoms for small-to-intermediate-sized trees, but were neutral for larger trees across elevations. Conspecific-density-dependent effects on growth were negative across all tree size classes and elevations. These findings reveal fundamental differences in biotic interactions that may contribute to relationships between species diversity, elevation and climate.
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- 2022
6. Author response for 'Tree species diversity increases with conspecific negative density dependence across an elevation gradient'
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null Joseph A. LaManna, null F. Andrew Jones, null David M. Bell, null Robert J. Pabst, and null David C. Shaw
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- 2021
7. Tree growth declines and mortality were associated with a parasitic plant during warm and dry climatic conditions in a temperate coniferous forest ecosystem
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David C. Shaw, David M. Bell, and Robert J. Pabst
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Washington ,0106 biological sciences ,010504 meteorology & atmospheric sciences ,Parasitic plant ,Forests ,010603 evolutionary biology ,01 natural sciences ,Trees ,Tsuga ,Temperate climate ,Animals ,Environmental Chemistry ,Ecosystem ,Temperate coniferous forest ,0105 earth and related environmental sciences ,General Environmental Science ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,Ecology ,biology ,Experimental forest ,biology.organism_classification ,Tracheophyta ,Productivity (ecology) ,Agronomy ,Western Hemlock - Abstract
Insects and pathogens are widely recognized as contributing to increased tree vulnerability to the projected future increasing frequency of hot and dry conditions, but the role of parasitic plants is poorly understood even though they are common throughout temperate coniferous forests in the western United States. We investigated the influence of western hemlock dwarf mistletoe (Arceuthobium tsugense) on large (≥45.7 cm diameter) western hemlock (Tsuga heterophylla) growth and mortality in a 500 year old coniferous forest at the Wind River Experimental Forest, Washington State, United States. We used five repeated measurements from a long-term tree record for 1,395 T. heterophylla individuals. Data were collected across a time gradient (1991-2014) capturing temperature increases and precipitation decreases. The dwarf mistletoe rating (DMR), a measure of infection intensity, varied among individuals. Our results indicated that warmer and drier conditions amplified dwarf mistletoe effects on T. heterophylla tree growth and mortality. We found that heavy infection (i.e., high DMR) resulted in reduced growth during all four measurement intervals, but during warm and dry intervals (a) growth declined across the entire population regardless of DMR level, and (b) both moderate and heavy infections resulted in greater growth declines compared to light infection levels. Mortality rates increased from cooler-wetter to warmer-drier measurement intervals, in part reflecting increasing mortality with decreasing tree growth. Mortality rates were positively related to DMR, but only during the warm and dry measurement intervals. These results imply that parasitic plants like dwarf mistletoe can amplify the impact of climatic stressors of trees, contributing to the vulnerability of forest landscapes to climate-induced productivity losses and mortality events.
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- 2019
8. Testing conceptual models of early plant succession across a disturbance gradient
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Andrés Holz, Joseph A. Antos, Cynthia C. Chang, James E. Cook, Donald B. Zobel, Dylan G. Fischer, Mark E. Swanson, Roger del Moral, Charles B. Halpern, Robert J. Pabst, Meghan L. Avolio, and Abir Biswas
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0106 biological sciences ,Secondary succession ,Disturbance (geology) ,Ecology ,Plant Science ,Ecological succession ,010603 evolutionary biology ,01 natural sciences ,Seral community ,Environmental science ,Ruderal species ,Species richness ,Rank abundance curve ,Primary succession ,Ecology, Evolution, Behavior and Systematics ,010606 plant biology & botany - Abstract
Studies of succession have a long history in ecology, but rigorous tests of general, unifying principles are rare. One barrier to these tests of theory is the paucity of longitudinal studies that span the broad gradients of disturbance severity that characterize large, infrequent disturbances. The cataclysmic eruption of Mount St. Helens (Washington, USA) in 1980 produced a heterogeneous landscape of disturbance conditions, including primary to secondary successional habitats, affording a unique opportunity to explore how rates and patterns of community change relate to disturbance severity, post‐eruption site conditions and time. In this novel synthesis, we combined data from three long‐term (c. 30‐year) studies to compare rates and patterns of community change across three ‘zones’ representing a gradient of disturbance severity: primary successional blast zone, secondary successional tree blowdown/standing snag zone and secondary successional intact forest canopy/tephra deposit zone. Consistent with theory, rates of change in most community metrics (species composition, species richness, species gain/loss and rank abundance) decreased with time across the disturbance gradient. Surprisingly, rates of change were often greatest at intermediate‐severity disturbance and similarly low at high‐ and low‐severity disturbance. There was little evidence of compositional convergence among or within zones, counter to theory. Within zones, rates of change did not differ among ‘site types’ defined by pre‐ or post‐eruption site characteristics (disturbance history, legacy effects or substrate characteristics). Synthesis. The hump‐shaped relationships with disturbance severity runs counter to the theory predicting that community change will be slower during primary than during secondary succession. The similarly low rates of change after high‐ and low‐severity disturbance reflect differing sets of controls: seed limitation and abiotic stress in the blast zone vs. vegetative re‐emergence and low light in the tephra zone. Sites subjected to intermediate‐severity disturbance were the most dynamic, supporting species with a greater diversity of regenerative traits and seral roles (ruderal, forest and non‐forest). Succession in this post‐eruption landscape reflects the complex, multifaceted nature of volcanic disturbance (including physical force, heating and burial) and the variety of ways in which biological systems can respond to these disturbance effects. Our results underscore the value of comparative studies of long‐term, ecological processes for testing the assumptions and predictions of successional theory.
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- 2019
9. Historical harvests reduce neighboring old‐growth basal area across a forest landscape
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Thomas A. Spies, David M. Bell, and Robert J. Pabst
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0106 biological sciences ,Clearcutting ,Canopy ,Conservation of Natural Resources ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Ecology ,Forest management ,Logging ,Elevation ,Forestry ,Forests ,Old-growth forest ,010603 evolutionary biology ,01 natural sciences ,Trees ,Basal area ,Oregon ,Disturbance (ecology) ,0105 earth and related environmental sciences - Abstract
While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old-growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30-m resolution live tree basal area maps in lower and middle elevation mature and old-growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (800 m) and a negative edge influence at moderate to high elevations (800 m). Surprisingly, we found no or weak effects of harvest age (13-60 yr) and harvest area (0.2-110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi-decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old-growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision-making in old-growth forest landscapes by broadening the traditional view of stand boundaries. Furthermore, the consequences of forest harvesting may reach across ownership boundaries, highlighting complex governance issues surrounding landscape management of old-growth forests.
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- 2017
10. Tree regeneration, understory development, and biomass dynamics following wildfire in a mountain hemlock (Tsuga mertensiana) forest
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Robert J. Pabst, Jane Kertis, and Steven A. Acker
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040101 forestry ,Biomass (ecology) ,010504 meteorology & atmospheric sciences ,biology ,Ecology ,Forestry ,04 agricultural and veterinary sciences ,Understory ,Vegetation ,Management, Monitoring, Policy and Law ,Tsuga mertensiana ,biology.organism_classification ,01 natural sciences ,Habitat ,0401 agriculture, forestry, and fisheries ,Environmental science ,Forb ,Coarse woody debris ,0105 earth and related environmental sciences ,Nature and Landscape Conservation ,Woody plant - Abstract
Processes initiated by wildfire largely determine ecological characteristics of forested landscapes in subsequent decades, including vegetation composition, habitat quality, carbon balance, and probability of fire recurrence. Post-fire biomass dynamics have rarely been observed directly for high-elevation forests of the Pacific Northwest. We examined changes in total biomass and its components (attrition of coarse woody debris (CWD), growth of shrubs and herbaceous plants, and tree recruitment) over the first 15 years following wildfire in a mountain hemlock (Tsuga mertensiana) forest in Oregon, using permanent plots representing random samples of four levels of fire-severity, from unburned to >90% tree mortality. Understory vegetation was transformed by fire, inasmuch as only shrubs were detected in unburned plots, while burned plots also had significant amounts of graminoids and forbs. Conifer recruitment was sparse in plots with high fire-severity two years after fire, but was abundant after 15 years. Recruitment was predominantly mountain hemlock and most were seedlings
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- 2017
11. Thinning and in-stream wood recruitment in riparian second growth forests in coastal Oregon and the use of buffers and tree tipping as mitigation
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Robert J. Pabst, S. E. Litschert, Lee Benda, and Gordon H. Reeves
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0106 biological sciences ,Hydrology ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Thinning ,Riparian buffer ,Agroforestry ,010604 marine biology & hydrobiology ,Forest management ,Forestry ,STREAMS ,01 natural sciences ,Current (stream) ,Environmental science ,Secondary forest ,Channel (geography) ,0105 earth and related environmental sciences ,Riparian zone - Abstract
Many aquatic habitats in coastal Oregon have been impacted by historic land use practices that led to losses of in-stream wood and associated degraded fish habitats. Many of these streams are now bordered by stands of dense second growth forests (30–80 years) that are incorporated into riparian buffer zones with low wood recruitment and storage. Thinning in riparian zones is one management option to increase the rate of large tree growth and eventually larger in-stream wood, however, it raises concern about impacts on current wood recruitment, among other issues. Using a forest growth simulation model coupled to a model of in-stream wood recruitment, we explore riparian management alternatives in a Douglas-fir plantation in coastal Oregon. Alternatives included: (1) no treatment, (2) single and double entry thinning, without and with a 10-m buffer, and (3) thinning combined with mechanical introduction of some portion of the thinned trees into the stream (tree tipping). Compared to no treatment, single and double entry thinning on one side of a channel, without a 10-m buffer, reduce cumulative in-stream wood volume by 33 and 42 %, respectively, after 100 years (includes decay). Maintaining a 10-m buffer reduces the in-stream wood loss to 7 % (single entry thin) and 11 % (double entry). To completely offset the losses of in-stream wood in a single entry thin (on one or both sides of the stream), in the absence or presence of a 10-m buffer, requires a 12–14 % rate of tree tipping. Relative to the no-treatment alternative, cumulative in-stream wood storage can be increased up to 24 % in a double-entry thin with no buffer by tipping 15–20 % of the thinned trees (increased to 48 % if thinning and tipping simultaneously on both sides of the stream). The predicted increases in in-stream wood that can occur during a thin with tree tipping may be effective for restoring fish habitat, particularly in aquatic systems that have poor habitat conditions and low levels of in-stream wood due to historic land use activities.
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- 2015
12. BioTIME: A database of biodiversity time series for the Anthropocene
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Grace E. Frank, Alecia Bellgrove, Flaviana Maluf Souza, Fakhrizal Setiawan, Vladimir G. Onipchenko, Miguel Barbosa, J. Emmett Duffy, Robert A. Davis, Giselda Durigan, Jan Vanaverbeke, Ricardo Rocha, Ana Paula Savassi-Coutinho, Francis Neat, Emily H. Stanley, Erkki Pulliainen, Vinicius Castro Souza, Stephen F. Newton, N. A. Mil'chakova, Annika Hofgaard, James A. Nelson, Elisabeth J. Cooper, Lisandro Benedetti-Cecchi, Sonja Wipf, Anders Enemar, Gabriel Barros Gonçalves de Souza, Claire Laguionie-Marchais, Dušan Adam, Robert N. L. Fitt, Christopher P. Bloch, Claus Bässler, Gediminas Vaitkus, Magdalena Błażewicz, Robert R. Twilley, Richard Condit, B.R. Ramesh, Chaolun Allen Chen, Grace E. P. Murphy, Kevin P. Robinson, Gal Badihi, Lars G. Rudstam, J. Jonathan Moore, David M. Paterson, Sarah R. Supp, Claire E. Widdicombe, Suzanne M. Remillard, Hans M. Verheye, Jill F. Johnstone, Claire H. Davies, Shane A. Blowes, Mark E. Harmon, Rick D. Stuart-Smith, Andrew J. Brooks, Gert Van Hoey, José Eduardo Rebelo, Anna Maria Fosaa, Tim S. Doherty, Jasper A. Slingsby, Francesco Pomati, Raphaël Pélissier, Ward Appeltans, José Manuel Arcos, Phaedra Budy, Victor H. Rivera-Monroy, Maria Teresa Zugliani Toniato, Anthony J. Richardson, Luiz Fernando Loureiro Fernandes, Christopher D. Stallings, Rowan Stanforth, David J. Kushner, A. A. Akhmetzhanova, Geraldo Antônio Daher Corrêa Franco, Alessandra Fidelis, Elizabeth Gorgone-Barbosa, Dave Watts, S.A. Tarigan, Timothy C. Bonebrake, Kent P. McFarland, Jonathan Belmaker, Shahar Malamud, Kamil Král, John D. Lloyd, Diane M. McKnight, Alessandra Rocha Kortz, Luise Hermanutz, Tore Johannessen, N. Ayyappan, Brian J. Bett, Haley Arnold, Fernando Rodrigues da Silva, Peter L. Meserve, Francisco Lloret, Nadejda A. Soudzilovskaia, Michael R. Willig, Linda A. Kuhnz, Esther Lévesque, Kwang-Tsao Shao, Sofía Sal, Robert D. Hollister, Andrew Rassweiler, Christoph F. J. Meyer, Jeffrey C. Oliver, Isla H. Myers-Smith, Graham J. Edgar, Jacek Siciński, Beatriz Salgado, Fábio Venturoli, Matt Bradford, Borgþór Magnússon, Edward Castañeda-Moya, Anne D. Bjorkman, Eric Post, Alain Paquette, Or Givan, Jonathan S. Lefcheck, Falk Huettmann, Fábio Lang da Silveira, Roberto Cazzolla Gatti, Thomas J. Valone, Sarah C. Elmendorf, Sinta Pardede, Esben Moland Olsen, Laura Siegwart Collier, Flavio Antonio Maës dos Santos, Andrew H. Baird, Cheol Min Lee, Robert B. Waide, Olivia Mendivil Ramos, David C. Lightfoot, Stefan B. Williams, Ute Jandt, David Janík, Stephen S. Hale, Robin Elahi, Andrew L. Rypel, S. K. Morgan Ernest, Jörg Müller, Gaius R. Shaver, Anna Jażdżewska, José Mauro Sterza, Maarten Stevens, Denise de Cerqueira Rossa-Feres, Dor Edelist, Martha Isabel Vallejo, Michael Paul Nelson, Conor Waldock, Ricardo Ribeiro Rodrigues, Sally Sherman, Dustin J. Wilgers, Sharon K. Collinge, Kristen T. Holeck, Josep Peñuelas, Douglas A. Kelt, Tiago Egydio Barreto, Faye Moyes, Robert L. Schooley, Peter B. Reich, Jason Meador, Anders Michelsen, J. Paul Richardson, Sara J. Snell, Julio R. Gutiérrez, Chih-hao Hsieh, Gary D. Grossman, Hernando García, Ana Carolina da Silva, Kyle J. A. Zawada, Richard T. Holmes, John C. Priscu, Christine L. Huffard, Christian Rixen, William O. McLarney, Julia A. Jones, Anne Tolvanen, William A. Gould, Maite Louzao, Alejandro Pérez-Matus, Donald L. Henshaw, Kathleen L. Prudic, Herbert H. T. Prins, Helge Bruelheide, Catalina S. Ruz, Rui P. Vieira, Gary P. Thiede, Erin C. Keeley, James H. Brown, William R. Fraser, Pieter Provoost, Andrew S. Hoey, Robert J. Pabst, Kerry D. Woods, Fabiano Turini Farah, Nancy B. Rybicki, Sara E. Scanga, Trevor J. Willis, Daniel J. Metcalfe, Mark Williamson, Joshua S. Madin, Tasrif Kartawijaya, Brian J. McGill, Erica M. Sampaio, Shannan K. Crow, Stephen P. Hubbell, Jochen Schmidt, Daniel C. Reed, Steven Degraer, Laura H. Antão, Krzysztof Pabis, Christopher C. Koenig, Fernando Carvalho, Marcelo Vianna, Anne E. Magurran, Marc Estiarte, Rebecca Kinnear, Tracey Smart, Lesley T. Lancaster, Frank P. Day, Natalia Norden, Unai Cotano, Fábio Z. Farneda, Nelson Valdivia, Corinna Gries, Tomasz Wesołowski, Pedro Higuchi, Jungwon Kang, Randall W. Myster, Itai van Rijn, Oscar Pizarro, Michael L. Zettler, Simon Thorn, Thomas W. Sherry, Timothy E. Dunn, Tung-Yung Fan, Susan Boyd, Adrià López-Baucells, Tomáš Vrška, Tory J. Chase, Ruben Escribano, R. Williams, Carolina Mathias Moreira, John F. Chamblee, Con Quang Vu, Halvor Knutsen, Amanda E. Bates, Maria Dornelas, Kari Klanderud, Jorge Yoshio Tamashiro, Tom Moens, Sara L. Webb, Iain Matthews, Carl Van Colen, Chao-Yang Kuo, Caya Sievers, Faith A. M. Jones, Gary Haskins, Eric J. Woehler, J. Hans C. Cornelissen, Allen H. Hurlbert, Mia O. Hoogenboom, Pamela Hidalgo, Henry A. Ruhl, Brian S. Evans, Ørjan Totland, Lien Van Vu, Yzel Rondon Súarez, Gabriella Damasceno, Even Moland, John Harte, Andrew Naumov, Ethan P. White, Natália Macedo Ivanauskas, Systems Ecology, International Oceanographic Data and Information Exchange (IODE) of the Intergovernmental Oceanographic Commission of UNESCO, Oostende, Safety science group, Delft University of Technology (TU Delft), Institut Français de Pondichéry (IFP), Centre National de la Recherche Scientifique (CNRS)-Ministère de l'Europe et des Affaires étrangères (MEAE), Department of Biology [Pisa], University of Pisa - Università di Pisa, CSIRO Land and Water, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Institute of Biology/Geobotany and Botanical Garden, Martin-Luther-Universität Halle Wittenberg (MLU), Management Unit of the Mathematical Model of the North Sea, Royal Belgian Insitute of Natural Sciences, Floresta Estadual Assis, Global Ecology Unit CREAF-CEAB-CSIC, Universitat Autònoma de Barcelona [Barcelona] (UAB), National Museum of Marine Biology and Aquarium, Universidade de São Paulo (USP), Polar Oceans Research Group [USA], Department of Zoology, Tel Aviv University [Tel Aviv], Norwegian Institute for Nature Research (NINA), EWHALE Laboratory of Biology and Wildlife Department, Institute of Arctic Biology-University of Alaska [Fairbanks] (UAF), Laboratory of Polar Biology and Oceanobiology, University of Lódź, Dept Ecol Evol Biol, Univ California SC (EEB-UCSC), University of California [Santa Cruz] (UCSC), University of California-University of California, Département de chimie-biologie & Centre d’études nordiques [CANADA], Université du Québec à Trois-Rivières (UQTR), Human Communication Technologies Research Laboratory (UBC), University of British Columbia (UBC), Instituto Espanol de Oceanografia, Instituto Español de Oceanografía, Department of Biology [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Institute of Marine Research, Flødevigen Marine Research Station, Computer Laboratory [Cambridge], University of Cambridge [UK] (CAM), Aarhus University [Aarhus], Evolution et Diversité Biologique (EDB), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre for Forest Research (CFR), Université du Québec à Montréal (UQAM), The Centre for Applied Genomics, Toronto, University of Toronto-The Hospital for Sick Children-Department of Molecular Genetics-McLaughlin Centre, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centro de Investigación Oceanográfica en el Pacífico Sur Oriental (COPAS), Universidad de Concepción [Chile], Department of Biology, Pennsylvania State University (Penn State), Penn State System-Penn State System, Department of Biological Science [Tallahassee], Florida State University [Tallahassee] (FSU), Department of Forest Resources, University of Minnesota [Twin Cities], University of Minnesota System-University of Minnesota System, WSL Institute for Snow and Avalanche Research SLF, Communication Systems Group [Zurich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Academia Sinica, Facultad Ciencias del Mar, universidad catolica del Norte, Marine Biology Section, Ghent University [Belgium] (UGENT), Department of Avian Ecology, Wrocław University, Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania (UTAS), European Project: 610028,EC:FP7:ERC,ERC-2013-SyG,IMBALANCE-P(2014), Dornelas, Maria, University of St Andrews. School of Biology, University of St Andrews. Fish Behaviour and Biodiversity Research Group, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Institute of Behavioural and Neural Sciences, University of St Andrews. St Andrews Sustainability Institute, University of St Andrews. Centre for Research into Ecological & Environmental Modelling, University of St Andrews. Sediment Ecology Research Group, University of St Andrews. Centre for Higher Education Research, Ministère de l'Europe et des Affaires étrangères (MEAE)-Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona (UAB), Universidade de São Paulo = University of São Paulo (USP), Tel Aviv University (TAU), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Flødevigen Research Station (IMR), Institute of Marine Research [Bergen] (IMR), University of Bergen (UiB)-University of Bergen (UiB), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université du Québec à Montréal = University of Québec in Montréal (UQAM), The Hospital for sick children [Toronto] (SickKids)-University of Toronto-Department of Molecular Genetics-McLaughlin Centre, Universidad de Concepción - University of Concepcion [Chile], University of Minnesota [Twin Cities] (UMN), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Universiteit Gent = Ghent University (UGENT), University of Wrocław [Poland] (UWr), Institute for Marine and Antarctic Studies [Hobart] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, University of Toronto-The Hospital for sick children [Toronto] (SickKids)-Department of Molecular Genetics-McLaughlin Centre, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), Universiteit Gent = Ghent University [Belgium] (UGENT), Dornelas M., Antao L.H., Moyes F., Bates A.E., Magurran A.E., Adam D., Akhmetzhanova A.A., Appeltans W., Arcos J.M., Arnold H., Ayyappan N., Badihi G., Baird A.H., Barbosa M., Barreto T.E., Bassler C., Bellgrove A., Belmaker J., Benedetti-Cecchi L., Bett B.J., Bjorkman A.D., Blazewicz M., Blowes S.A., Bloch C.P., Bonebrake T.C., Boyd S., Bradford M., Brooks A.J., Brown J.H., Bruelheide H., Budy P., Carvalho F., Castaneda-Moya E., Chen C.A., Chamblee J.F., Chase T.J., Siegwart Collier L., Collinge S.K., Condit R., Cooper E.J., Cornelissen J.H.C., Cotano U., Kyle Crow S., Damasceno G., Davies C.H., Davis R.A., Day F.P., Degraer S., Doherty T.S., Dunn T.E., Durigan G., Duffy J.E., Edelist D., Edgar G.J., Elahi R., Elmendorf S.C., Enemar A., Ernest S.K.M., Escribano R., Estiarte M., Evans B.S., Fan T.-Y., Turini Farah F., Loureiro Fernandes L., Farneda F.Z., Fidelis A., Fitt R., Fosaa A.M., Daher Correa Franco G.A., Frank G.E., Fraser W.R., Garcia H., Cazzolla Gatti R., Givan O., Gorgone-Barbosa E., Gould W.A., Gries C., Grossman G.D., Gutierrez J.R., Hale S., Harmon M.E., Harte J., Haskins G., Henshaw D.L., Hermanutz L., Hidalgo P., Higuchi P., Hoey A., Van Hoey G., Hofgaard A., Holeck K., Hollister R.D., Holmes R., Hoogenboom M., Hsieh C.-H., Hubbell S.P., Huettmann F., Huffard C.L., Hurlbert A.H., Macedo Ivanauskas N., Janik D., Jandt U., Jazdzewska A., Johannessen T., Johnstone J., Jones J., Jones F.A.M., Kang J., Kartawijaya T., Keeley E.C., Kelt D.A., Kinnear R., Klanderud K., Knutsen H., Koenig C.C., Kortz A.R., Kral K., Kuhnz L.A., Kuo C.-Y., Kushner D.J., Laguionie-Marchais C., Lancaster L.T., Min Lee C., Lefcheck J.S., Levesque E., Lightfoot D., Lloret F., Lloyd J.D., Lopez-Baucells A., Louzao M., Madin J.S., Magnusson B., Malamud S., Matthews I., McFarland K.P., McGill B., McKnight D., McLarney W.O., Meador J., Meserve P.L., Metcalfe D.J., Meyer C.F.J., Michelsen A., Milchakova N., Moens T., Moland E., Moore J., Mathias Moreira C., Muller J., Murphy G., Myers-Smith I.H., Myster R.W., Naumov A., Neat F., Nelson J.A., Paul Nelson M., Newton S.F., Norden N., Oliver J.C., Olsen E.M., Onipchenko V.G., Pabis K., Pabst R.J., Paquette A., Pardede S., Paterson D.M., Pelissier R., Penuelas J., Perez-Matus A., Pizarro O., Pomati F., Post E., Prins H.H.T., Priscu J.C., Provoost P., Prudic K.L., Pulliainen E., Ramesh B.R., Mendivil Ramos O., Rassweiler A., Rebelo J.E., Reed D.C., Reich P.B., Remillard S.M., Richardson A.J., Richardson J.P., van Rijn I., Rocha R., Rivera-Monroy V.H., Rixen C., Robinson K.P., Ribeiro Rodrigues R., de Cerqueira Rossa-Feres D., Rudstam L., Ruhl H., Ruz C.S., Sampaio E.M., Rybicki N., Rypel A., Sal S., Salgado B., Santos F.A.M., Savassi-Coutinho A.P., Scanga S., Schmidt J., Schooley R., Setiawan F., Shao K.-T., Shaver G.R., Sherman S., Sherry T.W., Sicinski J., Sievers C., da Silva A.C., Rodrigues da Silva F., Silveira F.L., Slingsby J., Smart T., Snell S.J., Soudzilovskaia N.A., Souza G.B.G., Maluf Souza F., Castro Souza V., Stallings C.D., Stanforth R., Stanley E.H., Mauro Sterza J., Stevens M., Stuart-Smith R., Rondon Suarez Y., Supp S., Yoshio Tamashiro J., Tarigan S., Thiede G.P., Thorn S., Tolvanen A., Teresa Zugliani Toniato M., Totland O., Twilley R.R., Vaitkus G., Valdivia N., Vallejo M.I., Valone T.J., Van Colen C., Vanaverbeke J., Venturoli F., Verheye H.M., Vianna M., Vieira R.P., Vrska T., Quang Vu C., Van Vu L., Waide R.B., Waldock C., Watts D., Webb S., Wesolowski T., White E.P., Widdicombe C.E., Wilgers D., Williams R., Williams S.B., Williamson M., Willig M.R., Willis T.J., Wipf S., Woods K.D., Woehler E.J., Zawada K., Zettler M.L., The Wellcome Trust, European Research Council, and University of St Andrews. Centre for Biological Diversity
- Subjects
Data Papers ,0106 biological sciences ,Range (biology) ,QH301 Biology ,temporal ,NERC ,Biodiversity ,Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480 [VDP] ,BIALOWIEZA NATIONAL-PARK ,special ,computer.software_genre ,[SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy ,01 natural sciences ,species richness ,SDG 15 - Life on Land ,biodiversity ,Global and Planetary Change ,B003-ecology ,Database ,Ecology ,Sampling (statistics) ,SIMULATED HERBIVORY ,supporting technologies ,LAND-BRIDGE ISLANDS ,[SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics ,PE&RC ,global ,PRIMEVAL TEMPERATE FOREST ,Geography ,POPULATION TRENDS ,turnover ,Data Paper ,SECONDARY FOREST ,Evolution ,ESTUARINE COASTAL LAGOON ,010603 evolutionary biology ,QH301 ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,Behavior and Systematics ,Anthropocene ,spatial ,Ecology, Evolution, Behavior and Systematics ,VDP::Mathematics and natural science: 400::Zoology and botany: 480 ,species richne ,14. Life underwater ,SDG 14 - Life Below Water ,NE/L002531/1 ,ZA4450 ,Relative species abundance ,ZA4450 Databases ,010604 marine biology & hydrobiology ,RCUK ,Biology and Life Sciences ,DAS ,15. Life on land ,DECIDUOUS FOREST ,Taxon ,Fish ,13. Climate action ,MCP ,Wildlife Ecology and Conservation ,LONG-TERM CHANGE ,Species richness ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,computer ,BIRD COMMUNITY DYNAMICS ,VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480 - Abstract
Motivation The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. Main types of variables included The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. Spatial location and grain BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). Time period and grain BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. Major taxa and level of measurement BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates. Software format .csv and .SQL., Global Ecology and Biogeography, 27 (7), ISSN:1466-822X, ISSN:1466-8238
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- 2018
13. Testing predictions of forest succession using long-term measurements: 100 yrs of observations in the Oregon Cascades
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Mark E. Harmon and Robert J. Pabst
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Ecology ,Environmental science ,Plant Science ,Ecological succession ,Term (time) - Published
- 2015
14. Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA
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Cynthia Schwartz, Emily Platt, Alan A. Ager, Ana M. G. Barros, Thomas A. Spies, Susan Charnley, John D. Bailey, Jennifer Koch, Michelle M. Steen-Adams, Peter H. Singleton, Jeffrey D. Kline, Keith A. Olsen, Robert J. Pabst, Eric M. White, John Bolte, Blair Csuti, Anita T. Morzillo, and James M. Sulzman
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010504 meteorology & atmospheric sciences ,QH301-705.5 ,Forest management ,adaptation ,010501 environmental sciences ,Woodpecker ,01 natural sciences ,wildfire ,Ecosystem services ,Empirical research ,Biology (General) ,Land tenure ,QH540-549.5 ,0105 earth and related environmental sciences ,Agent-based model ,biology ,Ecology ,business.industry ,Environmental resource management ,landscape ,biology.organism_classification ,Geography ,Habitat ,Northern spotted owl ,business ,ecosystem services ,management - Abstract
Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landscape in the eastern Cascades of Oregon. Our model incorporated existing models of vegetation succession and fire spread and information from original empirical studies of landowner decision making. Our findings indicate that alternative management strategies can have variable effects on landscape outcomes over 50 years for fire, socioeconomic, and ecosystem services metrics. For example, scenarios with federal restoration treatments had slightly less high-severity fire than a scenario without treatment; exposure of homes in the wildland-urban interface to fire was also slightly less with restoration treatments compared to no management. Treatments appeared to be more effective at reducing high-severity fire in years with more fire than in years with less fire. Under the current management scenario, timber production could be maintained for at least 50 years on federal lands. Under an accelerated restoration scenario, timber production fell because of a shortage of areas meeting current stand structure treatment targets. Trade-offs between restoration outcomes (e.g., open forests with large fire-resistant trees) and habitat for species that require dense older forests were evident. For example, the proportional area of nesting habitat for northern spotted owl (Strix occidentalis) was somewhat less after 50 years under the restoration scenarios than under no management. However, the amount of resilient older forest structure and habitat for white-headed woodpecker (Leuconotopicus albolarvatus) was higher after 50 years under active management. More carbon was stored on this landscape without management than with management, despite the occurrence of high-severity wildfire. Our results and further applications of the model could be used in collaborative settings to facilitate discussion and development of policies and practices for fire-prone landscapes.
- Published
- 2017
15. Spatiotemporal dynamics of simulated wildfire, forest management, and forest succession in central Oregon, USA
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John D. Bailey, Haiganoush K. Preisler, Alan A. Ager, Emily Platt, Ana M. G. Barros, Michelle A. Day, Keith A. Olsen, Robert J. Pabst, Thomas A. Spies, John Bolte, and Eric M. White
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0106 biological sciences ,Agent-based model ,010504 meteorology & atmospheric sciences ,Ecology ,QH301-705.5 ,Forest management ,state-and-transition model ,Ecological succession ,agent-based model ,Deschutes National Forest ,010603 evolutionary biology ,01 natural sciences ,Environmental science ,Flammap ,minimum travel time ,Biology (General) ,QH540-549.5 ,0105 earth and related environmental sciences - Abstract
We use the simulation model Envision to analyze long-term wildfire dynamics and the effects of different fuel management scenarios in central Oregon, USA. We simulated a 50-year future where fuel management activities were increased by doubling and tripling the current area treated while retaining existing treatment strategies in terms of spatial distribution and treatment type. We modeled forest succession using a state-and-transition approach and simulated wildfires based on the contemporary fire regime of the region. We tested for the presence of temporal trends and overall differences in burned area among four fuel management scenarios. Results showed that when the forest was managed to reduce fuels it burned less: over the course of 50 years there was up to a 40% reduction in area burned. However, simulation outputs did not reveal the expected temporal trend, i.e., area burned did not decrease progressively with time, nor did the absence of management lead to its increase. These results can be explained as the consequence of an existing wildfire deficit and vegetation succession paths that led to closed canopy, and heavy fuels forest types that are unlikely to burn under average fire weather. Fire (and management) remained relatively rare disturbances and, given our assumptions, were unable to alter long-term vegetation patterns and consequently unable to alter long-term wildfire dynamics. Doubling and tripling current management targets were effective in the near term but not sustainable through time because of a scarcity of stands eligible to treat according to the modeled management constraints. These results provide new insights into the long-term dynamics between fuel management programs and wildfire and demonstrate that treatment prioritization strategies have limited effect on fire activity if they are too narrowly focused on particular forest conditions.
- Published
- 2017
16. Complex mountain terrain and disturbance history drive variation in forest aboveground live carbon density in the western Oregon Cascades, USA
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Thomas A. Spies, Harold S. J. Zald, E. Ashley Steel, Keith A. Olsen, Robert J. Pabst, and Rupert Seidl
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0106 biological sciences ,Watershed ,010504 meteorology & atmospheric sciences ,Ecology ,Forest management ,Logging ,Forestry ,Experimental forest ,Management, Monitoring, Policy and Law ,Carbon sequestration ,010603 evolutionary biology ,01 natural sciences ,Article ,Disturbance (ecology) ,Forest ecology ,Environmental science ,Spatial variability ,Physical geography ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Forest carbon (C) density varies tremendously across space due to the inherent heterogeneity of forest ecosystems. Variation of forest C density is especially pronounced in mountainous terrain, where environmental gradients are compressed and vary at multiple spatial scales. Additionally, the influence of environmental gradients may vary with forest age and developmental stage, an important consideration as forest landscapes often have a diversity of stand ages from past management and other disturbance agents. Quantifying forest C density and its underlying environmental determinants in mountain terrain has remained challenging because many available data sources lack the spatial grain and ecological resolution needed at both stand and landscape scales. The objective of this study was to determine if environmental factors influencing aboveground live carbon (ALC) density differed between young versus old forests. We integrated aerial light detection and ranging (lidar) data with 702 field plots to map forest ALC density at a grain of 25 m across the H.J. Andrews Experimental Forest, a 6369 ha watershed in the Cascade Mountains of Oregon, USA. We used linear regressions, random forest ensemble learning (RF) and sequential autoregressive modeling (SAR) to reveal how mapped forest ALC density was related to climate, topography, soils, and past disturbance history (timber harvesting and wildfires). ALC increased with stand age in young managed forests, with much greater variation of ALC in relation to years since wildfire in old unmanaged forests. Timber harvesting was the most important driver of ALC across the entire watershed, despite occurring on only 23% of the landscape. More variation in forest ALC density was explained in models of young managed forests than in models of old unmanaged forests. Besides stand age, ALC density in young managed forests was driven by factors influencing site productivity, whereas variation in ALC density in old unmanaged forests was also affected by finer scale topographic conditions associated with sheltered sites. Past wildfires only had a small influence on current ALC density, which may be a result of long times since fire and/or prevalence of non-stand replacing fire. Our results indicate that forest ALC density depends on a suite of multi-scale environmental drivers mediated by complex mountain topography, and that these relationships are dependent on stand age. The high and context-dependent spatial variability of forest ALC density has implications for quantifying forest carbon stores, establishing upper bounds of potential carbon sequestration, and scaling field data to landscape and regional scales.
- Published
- 2016
17. Canopy gaps affect long-term patterns of tree growth and mortality in mature and old-growth forests in the Pacific Northwest
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Robert J. Pabst, Andrew N. Gray, and Thomas A. Spies
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Canopy ,education.field_of_study ,geography ,geography.geographical_feature_category ,Ecology ,Population ,Crown (botany) ,Forestry ,Understory ,Vegetation ,Management, Monitoring, Policy and Law ,Biology ,Old-growth forest ,Spatial heterogeneity ,Spatial variability ,education ,Nature and Landscape Conservation - Abstract
Canopy gaps created by tree mortality can affect the speed and trajectory of vegetation growth, species’ population dynamics, and spatial heterogeneity in mature forests. Most studies focus on plant development within gaps, yet gaps also affect the mortality and growth of surrounding trees, which influence shading and root encroachment into gaps and determine whether, and how quickly, a gap becomes occupied by recovering vegetation. The objective of this study was to determine the effect of canopy gap size on mortality and growth of surrounding trees over a 16-year period in mature and old-growth Douglas-fir dominated forests in the coastal Pacific Northwest, USA. Replicates of four sizes of experimental gaps and controls were created in two mature stands (90 and 145-years old) and two old-growth stands (overstory trees 350–525-years old); mortality and diameter of surrounding trees were measured periodically over 16 years. A subset of trees was cored to compare growth increment before and after gap creation. There was no difference between mortality rates of trees within 8 m of gaps and trees in closed-canopy controls, although mortality causes did differ for understory trees. Mortality of understory trees was higher at gap edges than in controls, but lower several meters into the forest, suggesting a shift from negative to positive effects with the gradient in exposure. Diameter growth rates of trees were greater next to gaps than in controls, with the greatest difference ranging from 39% for overstory trees to 111% for understory trees in mature stands. Growth rates of trees in old-growth stands differed by crown class and position around gap, suggesting an effect of direct solar radiation. Growth rates of trees in mature stands were relatively insensitive to gap size and position, suggesting that increased soil moisture drove responses in these stands. Somewhat unexpectedly, there were rapid increases in growth in some old-growth trees, but not in the largest gap sizes. Results suggest canopy gaps can create heterogeneity of ecosystem function through spatial variation in effects on growth and mortality across mature and old-growth stands.
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- 2012
18. Multi-scale Drivers of Spatial Variation in Old-Growth Forest Carbon Density Disentangled with Lidar and an Individual-Based Landscape Model
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Werner Rammer, E. Ashley Steel, Rupert Seidl, Keith A. Olsen, Robert J. Pabst, and Thomas A. Spies
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geography ,geography.geographical_feature_category ,Ecology ,Global warming ,Biodiversity ,Old-growth forest ,Climate change mitigation ,Forest ecology ,Ecosystem management ,Environmental Chemistry ,Environmental science ,Ecosystem ,Spatial variability ,Ecology, Evolution, Behavior and Systematics - Abstract
Forest ecosystems are the most important terrestrial carbon (C) storage globally, and presently mitigate anthropogenic climate change by acting as a large and persistent sink for atmospheric CO2. Yet, forest C density varies greatly in space, both globally and at stand and landscape levels. Understanding the multi-scale drivers of this variation is a prerequisite for robust and effective climate change mitigation in ecosystem management. Here, we used airborne light detection and ranging (Lidar) and a novel highresolution simulation model of landscape dynamics (iLand) to identify the drivers of variation in C density for an old-growth forest landscape in Oregon, USA. With total ecosystem C in excess of 1G t ha -1 these ecosystems are among the most C-rich globally. Our findings revealed considerable spatial variability in stand-level C density across the landscape. Notwithstanding the distinct environmental gradients in our mountainous study area only 55.3% of this variation was explained by environmental drivers, with radiation and soil physical properties having a stronger influence than temperature and precipitation. The remaining variation in C stocks was largely attributable to emerging properties of stand dynamics (that is, stand structure and composition). Not only were density- and sizerelated indicators positively associated with C stocks but also diversity in composition and structure, documenting a close link between biodiversity and ecosystem functioning. We conclude that the complexity of old-growth forests contributes to their sustained high C levels, a finding that is relevant to managing forests for climate change mitigation.
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- 2012
19. Potential future dead wood dynamics in a multi-ownership region: The Coastal Province of Oregon, USA
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Keith A. Olsen, Robert J. Pabst, Thomas A. Spies, and Rebecca S.H. Kennedy
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Ecology ,Agroforestry ,Forest management ,Biodiversity ,Land management ,Forestry ,Management, Monitoring, Policy and Law ,Snag ,Disturbance (ecology) ,Forest ecology ,Environmental science ,Ecosystem ,Nature and Landscape Conservation ,Woody plant - Abstract
Dead wood is important to the processes, structural complexity, and biodiversity of forested ecosystems. Forest management may have unforeseen consequences to dead wood via the interaction of proposed activities with the legacy of past management, natural disturbance, and site productivity. We assessed the potential effects of future forest management for a 300-year period across a large (ca. 23,000 km2) forested region that contains numerous ownerships and land management strategies. To do this, we used an ecological gap model (ZELIG), a dead wood decomposition dynamics model (CWDM), live and dead wood data from a physiographic province-wide plot database, and ownership- and land-allocation-specific management prescriptions. Dead wood amounts were projected to increase over the simulation period across the region, primarily because conservation-oriented management approaches utilized on federal lands increased the volume of large logs and snags and number of large snags on federal lands. Large snags and logs decreased on forest industry lands as legacy dead wood derived from historical natural disturbance events was not replaced through management. The results of this study provide an estimate of the maximum potential amounts of dead wood in the forests of the Coastal Province of Oregon, USA, under current policies and forest management, given model assumptions. In cases where current amounts of dead wood may be lower than those present historically, conservation-oriented policies designed to maintain or increase dead wood amounts, such as the Northwest Forest Plan, may have a strong positive influence on large dead wood abundance and related biodiversity in parts of a region that are also under intensive management.
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- 2010
20. Calibrating and testing a gap model for simulating forest management in the Oregon Coast Range
- Author
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Steven L. Garman, Matthew N. Goslin, Thomas A. Spies, and Robert J. Pabst
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Forest inventory ,biology ,Ecology ,Forest management ,Forestry ,Understory ,Ecological succession ,Management, Monitoring, Policy and Law ,biology.organism_classification ,Alder ,Basal area ,Ecosystem model ,Forest ecology ,Environmental science ,Nature and Landscape Conservation - Abstract
The complex mix of economic and ecological objectives facing today's forest managers necessitates the development of growth models with a capacity for simulating a wide range of forest conditions while producing outputs useful for economic analyses. We calibrated the gap model ZELIG to simulate stand-level forest development in the Oregon Coast Range as part of a landscape-scale assessment of different forest management strategies. Our goal was to incorporate the predictive ability of an empirical model with the flexibility of a forest succession model. We emphasized the development of commercial-aged stands of Douglas-fir, the dominant tree species in the study area and primary source of timber. In addition, we judged that the ecological approach of ZELIG would be robust to the variety of other forest conditions and practices encountered in the Coast Range, including mixed-species stands, small-scale gap formation, innovative silvicultural methods, and reserve areas where forests grow unmanaged for long periods of time. We parameterized the model to distinguish forest development among two ecoregions, three forest types and two site productivity classes using three data sources: chronosequences of forest inventory data, long-term research data, and simulations from an empirical growth-and-yield model. The calibrated model was tested with independent, long-term measurements from 11 Douglas-fir plots (6 unthinned, 5 thinned), 3 spruce-hemlock plots, and 1 red alder plot. ZELIG closely approximated developmental trajectories of basal area and large trees in the Douglas-fir plots. Differences between simulated and observed conifer basal area for these plots ranged from −2.6 to 2.4 m2/ha; differences in the number of trees/ha ≥50 cm dbh ranged from −8.8 to 7.3 tph. Achieving these results required the use of a diameter-growth multiplier, suggesting some underlying constraints on tree growth such as the temperature response function. ZELIG also tended to overestimate regeneration of shade-tolerant trees and underestimate total tree density (i.e., higher rates of tree mortality). However, comparisons with the chronosequences of forest inventory data indicated that the simulated data are within the range of variability observed in the Coast Range. Further exploration and improvement of ZELIG is warranted in three key areas: (1) modeling rapid rates of conifer tree growth without the need for a diameter-growth multiplier; (2) understanding and remedying rates of tree mortality that were higher than those observed in the independent data; and (3) improving the tree regeneration module to account for competition with understory vegetation.
- Published
- 2008
21. Rate of tree carbon accumulation increases continuously with tree size
- Author
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Sheng-Hsin Su, David A. Coomes, David Kenfack, Noelle G. Beckman, William K. Morris, Lucio R. Malizia, Emily R. Lines, Olivier Flores, George B. Chuyong, Nadja Rüger, Jean-Remy Makana, Eric A. Álvarez, Patrick J. Baker, Stephen P. Hubbell, Mark E. Harmon, Susan K. Wiser, Zhanqing Hao, Corneille E. N. Ewango, Nathan L. Stephenson, Jerry F. Franklin, Sylvester Tan, Adrian J. Das, Agustina Malizia, Duncan W. Thomas, I-Fang Sun, Miguel A. Zavala, Cecilia Blundo, Hector Ricardo Grau, Richard Condit, Yiching Lin, Xugao Wang, Sarayudh Bunyavejchewin, Nantachai Pongpattananurak, Stuart J. Davies, Alvaro Duque, Robert J. Pabst, Sabrina E. Russo, and P. J. van Mantgem
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Aging ,Time Factors ,Climate ,Biology ,Models, Biological ,Carbon Cycle ,Trees ,Carbon cycle ,Ciencias Biológicas ,Species Specificity ,Forest ecology ,Body Size ,Biomass ,Carbon Accumulation ,Tree Size ,Tropical Climate ,Biomass (ecology) ,Multidisciplinary ,Geography ,Ecology ,Primary production ,Ecología ,Carbon ,Plant Leaves ,Tree (data structure) ,Productivity (ecology) ,Sample Size ,Greenhouse gas ,Ecosystem ecology ,CIENCIAS NATURALES Y EXACTAS - Abstract
Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage— increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute treemass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth,inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence. Fil: Blundo, Cecilia Mabel. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Malizia, Agustina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Malizia, L. R.. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; Argentina
- Published
- 2014
22. TEN YEARS OF VEGETATION SUCCESSION ON A DEBRIS-FLOW DEPOSIT IN OREGON
- Author
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Robert J. Pabst and Thomas A. Spies
- Subjects
education.field_of_study ,geography ,geography.geographical_feature_category ,Ecology ,biology ,Population ,Plant community ,Ecological succession ,biology.organism_classification ,Alder ,Propagule ,education ,Shade tolerance ,Earth-Surface Processes ,Water Science and Technology ,Woody plant ,Riparian zone - Abstract
We tracked vegetation succession on a debris-flow deposit in Oregon's Coast Range to examine factors influencing the development of riparian plant communities following disturbance. Plots were stratified across five areas of the deposit (bank slump, seep, upper and lower sediment wedge, log jam) the first growing season after debris flow. At six times during the next ten years we estimated cover of vascular plants and tallied density of woody plants. Plant colonization occurred within two years. Total cover increased two-to seven-fold on the five areas within three years. Red alder and salmonberry were the dominant species, although weedy herbs persisted where woody species were lacking. Ordination of cover data showed that the five areas remained floristically distinct over time, while undergoing similar shifts related to the increasing dominance of alder and salmonberry. Rapid height growth of alder allowed it to outcompete salmonberry and effectively capture most areas by the tenth year, even where sprouts from transported rhizomes gave salmonberry an early advantage. Our results suggest that successional patterns were influenced by substrate variability, species composition of initial colonizers, propagule sources and their distribution, and species life-history traits such as growth rate, competitive ability, and shade tolerance.
- Published
- 2001
23. Structure and composition of unmanaged riparian forests in the coastal mountains of Oregon, U.S.A
- Author
-
Robert J. Pabst and Thomas A. Spies
- Subjects
Global and Planetary Change ,geography ,geography.geographical_feature_category ,Ecology ,Drainage basin ,Forestry ,Vegetation dynamics ,Old-growth forest ,Basal area ,Riparian forest ,Spatial variability ,Mountain forest ,Riparian zone - Abstract
We characterized the structure and composition of unmanaged riparian forests in three river basins in Oregon's coastal mountains. Our objective was to evaluate stand attributes at three spatial scales: streamside (site), drainage network (stream order), and basin (subregion). Data on basal area, species composition, snag density, canopy cover, and tree regeneration were collected along transects at 124 sites. Conifer basal area increased with distance from stream, a trend similar among subregions, and was highest at sites along first-order streams. Hardwood basal area was relatively constant with distance from stream and was proportionally higher at sites along second- and third-order streams than at sites along first-order streams. Conifer and hardwood tree regeneration occurred infrequently and varied by topographic position, stream order, and subregion. Conifer regeneration was associated with basal area of shade-tolerant conifers and appeared to be limited by shrub competition. The unmanaged forests we studied were characterized by a patchy mosaic of structure and composition. Hardwoods and shrubs were major components of the near-stream environment in these forests, whereas dominance of conifers was limited to hillslopes. It appears that fine-scale patterns associated with proximity to the stream are influenced by coarser scale factors such as valley-floor width and climate.
- Published
- 1999
24. Distribution of herbs and shrubs in relation to landform and canopy cover in riparian forests of coastal Oregon
- Author
-
Robert J. Pabst and Thomas A. Spies
- Subjects
geography ,Tree canopy ,geography.geographical_feature_category ,Ecology ,Landform ,Species diversity ,Riparian forest ,Plant community ,Vegetation ,Plant Science ,Biology ,Environmental gradient ,Riparian zone - Abstract
In this study we characterized the distribution of herb and shrub species relative to landform and forest canopy attributes of streamside forests in the moist, conifer-dominated mountains of coastal Oregon. Species cover and environmental data were collected along transects at 94 sites. Species with relatively similar distributions were classified into 10 species groups to identify major patterns in the vegetation. Although these patterns were highly variable, ordination and gradient analyses indicated that vegetation composition is ordered along a complex environmental gradient running from streamside to hillslope. Similarly, species diversity followed a decreasing trend from active fluvial surfaces to lower hillslopes. Vegetation patterns were related to specific landforms, topographic positions, microsites, and coniferous tree cover within the trans-riparian gradient. We hypothesize that the environmental features correlated with these patterns are surrogates for the underlying mechanisms responsible for them. These are (i) hillslope processes and associated moisture gradients; (ii) hydrological disturbance; (iii) tolerance of saturated, valley-floor soils; (iv) shade tolerance; and (v) mineral soil disturbance. This study indicates that valley-floor and lower-slope plant communities are distinct elements in these forest landscapes, supporting the assumption that riparian zones require a different management and conservation strategy than upland forest communities.Key words: riparian vegetation, ordination, gradient analysis, species groups, landform. Nomenclature is based on that of Hitchcock and Cronquist (1973).
- Published
- 1998
25. Varying densities of Pacific madrone in a young stand in Oregon alter soil water-potential, plant moisture stress, and growth of Douglas fir
- Author
-
Robert J. Pabst, John C. Tappeiner, and Michael Newton
- Subjects
Stand development ,ved/biology ,ved/biology.organism_classification_rank.species ,Moisture stress ,Forestry ,Management, Monitoring, Policy and Law ,Herbaceous plant ,Biology ,biology.organism_classification ,Shrub ,Plant ecology ,Arbutus menziesii ,Horticulture ,Water potential ,Botany ,Nature and Landscape Conservation ,Woody plant - Abstract
Soil water-potential and Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] moisture stress and growth were studied on a droughty, 2-ha site in southwest Oregon where Pacific madrone (Arbutus menziesii Pursh) and associated shrub and herbaceous vegetation were thinned to represent the following range of conditions: high-density madrone (H), with associated shrubs and herbs controlled; medium-density madrone (M), shrubs and herbs controlled; low-density madrone (L), shrubs and herbs controlled; no madrone (N), shrubs and herbs controlled; and no madrone (U), shrubs and herbs predominate. Soil water-potential (Ψs) at a depth of 0–30 cm was consistently higher in treatment N than in all other treatments; in 1987 this difference was significant (P Predawn plant moisture stress ( pms ) of Douglas fir was significantly (P=0.0001) less in treatment N than in all other treatments. Seasonal moisture-stress relief ( smsr ) of Douglas fir was significantly related to madrone leaf area index (L) (r2=0.75, P=0.003), and was greatest in treatment N. Seasonal moisture-stress relief of madrone was also significantly correlated with L (r2=0.66, P=0.03). There were highly significant linear relationships between both predawn and midday pms and soil water-potential for Douglas fir (r2=0.76 and 0.75) and madrone (r2=0.69 and 0.79). Results clearly show that conditions for maximum Douglas-fir growth occurred in treatment N, in which all madrone and the associated vegetation were controlled. Average diameter growth of Douglas fir was greatest in treatment N, although not significantly different from that in treatment U, and least in treatment H. In 1987, Douglas-fir growth in diameter, stem basal-area, and stem volume was strongly related to smsr (r2=0.62–0.81) and madrone L (r2=0.66–0.87), and to a lesser extent, seasonal soil tension relief ( sstr ) (r2=0.51–0.62).
- Published
- 1990
26. Potential effects of forest policies on terrestrial biodiversity in a multi-ownership province
- Author
-
Michael T. McGrath, Keith A. Olsen, Robert J. Pabst, Brenda McComb, Thomas A. Spies, and Rebecca S.H. Kennedy
- Subjects
geography ,geography.geographical_feature_category ,Ecology ,Agroforestry ,Range (biology) ,Ownership ,Biodiversity ,Wildlife ,Vegetation ,Environment ,Old-growth forest ,Forest restoration ,Trees ,Oregon ,Habitat ,Species Specificity ,Intact forest landscape - Abstract
We used spatial simulation models to evaluate how current and two alternative policies might affect potential biodiversity over 100 years in the Coast Ranges Physiographic Province of Oregon. This 2.3-million-ha province is characterized by a diversity of public and private forest owners, and a wide range of forest policy and management objectives. We evaluated habitat availability for seven focal species representing different life histories. We also examined how policies affected old-growth stand structure, age distributions relative to the historical range of variability, and landscape patterns of forest types. Under the current policy scenario, the area of habitat for old-growth forest structure and associated species increased over time, the habitat for some early-successional associates remained stable, and the area of hardwood vegetation and diverse early-successional stages declined. The province is projected to move toward but not reach the historical range of variation of forest age classes that may have occurred under the wildfire regimes of the pre-Euroamerican settlement period. Ownership explained much of the pattern of biodiversity in the province, and under the current policy scenario, its effect increased over time as the landscape diverged into highly contrasting forest structures and ages. Patch type diversity declined slightly overall but declined strongly within ownerships. Most of the modeled change in biodiversity over time resulted from policies on public forest lands that were intended to increase the area of late-successional forests and species. One of the alternative policies, increased retention of wildlife trees on private lands, reduced the contrast between ownerships and increased habitat availability over time for both early- and late-successional species. Analysis of another alternative, stopping thinning of plantations on federal lands, indicated that current thinning regimes improve habitat for the Olive-sided Flycatcher, but the no-thinning alternative had no effect on the habitat scores for the late-successional species in the 100-year simulation. A comparison of indicators of biological diversity suggests that using focal species and forest structural measures can provide complementary information on biodiversity. The multi-ownership perspective provided a more complete synthesis of province-wide biodiversity patterns than assessments based on single ownerships.
- Published
- 2007
27. Interactive visual analysis promotes exploration of long-term ecological data
- Author
-
Ronald Metoyer, Frederick J. Swanson, Robert J. Pabst, Julia A. Jones, and Tuan Pham
- Subjects
Service (systems architecture) ,Ecology ,Computer science ,business.industry ,media_common.quotation_subject ,Usability ,Data science ,Visualization ,Information visualization ,Interactivity ,Interactive visual analysis ,business ,Set (psychology) ,Function (engineering) ,Ecology, Evolution, Behavior and Systematics ,media_common - Abstract
Long-term ecological data are crucial in helping ecologists understand ecosystem function and environmental change. Nevertheless, these kinds of data sets are difficult to analyze because they are usually large, multivariate, and spatiotemporal. Although existing analysis tools such as statistical methods and spreadsheet software permit rigorous tests of pre-conceived hypotheses and static charts for simple data exploration, they have limited capacity to provide an overview of the data and to enable ecologists to explore data iteratively, and interactively, before committing to statistical analysis. These issues hinder how ecologists gain knowledge and generate hypotheses from long-term data. We present Ecological Distributions and Trends Explorer (EcoDATE), a web-based, visual-analysis tool that facilitates exploratory analysis of long-term ecological data (i.e., generating hypotheses as opposed to confirming hypotheses). The tool, which is publicly available online, was created and refined through a user-centered design process in which our team of ecologists and visualization researchers collaborated closely. The results of our collaboration were (1) a set of visual representation and interaction techniques well suited to communicating distribution patterns and temporal trends in ecological data sets, and (2) an understanding of processes ecologists use to explore data and generate and test hypotheses. We present three case studies to demonstrate the utility of EcoDATE and the exploratory analysis processes using long-term data on cone production, stream chemistry, and forest structure collected as part of the H.J. Andrews Experimental Forest (HJA), Long Term Ecological Research (LTER), and US Forest Service Pacific Northwest Research Station programs. We also present results from a survey of 15 participants of a working group at the 2012 LTER All Scientists Meeting that showed that users appreciated the tool for its ease of use, holistic access to large data sets, and interactivity.
- Published
- 2013
28. Stem Treatments to Control Tanoak Sprouting
- Author
-
Robert J. Pabst, John C. Tapppeiner, and Michael Cloughesy
- Subjects
Horticulture ,Forestry ,Plant Science ,Biology ,Sprouting - Abstract
Applying 2,4-D, triclopyr, and picloram + 2,4-D to cut surfaces of tanoak (Lithocarpus densiflorus) on southwest Oregon sites in November or February increased mortality and reduced total sprout length and clump area relative to May or August applications. Injecting the same herbicides into stem frills caused 80 to 99% mean crown dieback for November, February, and May applications, but only 47% for August applications. Spraying triclopyr diluted with diesel oil to 1 5 or 3.0% on stem bases caused 64% mean crown dieback for August applications but only 28% averaged over the other three dates. Both frill and spray treatments reduced by about 1.5 to 3.0 times the sprout length and clump area of trees felled within 3 months of treatments, compared to untreated trees. Tanoak can be effectively controlled by treating cut surfaces when felling, and by stem injection or basal spray 3 months before harvesting or slashing for site preparation. Cut-surface application or injection from fall through early spring is likely to be most effective. West. J. Appl. For. 2(2):41-45, April 1987.
- Published
- 1987
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